1. Field
The present application relates generally to communications, and more specifically to handoffs from a long-term evolution (LTE) network to an evolved high rate packet data (eHRPD) network.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice and data. Typical wireless communication systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like. Additionally, the systems can conform to specifications such as third generation partnership project (3GPP), 3GPP2, 3GPP long-term evolution (LTE), LTE Advanced (LTE-A), etc.
Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations.
As the demand for high-rate and multimedia data services rapidly grows, there has been an effort toward implementation of efficient and robust communication systems with enhanced performance. For example, in recent years, users have started to replace fixed line communications with mobile communications and have increasingly demanded high voice quality, reliable service, and low prices.
To accommodate increasing demand, evolution of core networks of wireless communication systems followed from evolution of radio interfaces. For example, System Architecture Evolution (SAE) lead by 3GPP aims to evolve a Global System for Mobile communications (GSM)/General Packet Radio Service (GPRS) core network. The resultant Evolved Packet Core (EPC) is a multi-access core network based on the Internet Protocol (IP) that enables operators to deploy and utilize one common packet-based core network with a plurality of radio access technologies. The EPC provides optimized mobility for mobile devices and enables efficient handovers between different radio access technologies (e.g., between LTE and High Rate Packet Data (HRPD)). In addition, standardized roaming interfaces enable operators to offer services to subscribers across a variety of access technologies.